The second commandment we are given from God is not to make idols and images or be given to idolatry. In a way (and its most common interpretation) it simply continues the commandment before it, in which God tells us not to have any other gods before Him. However, we would not consider this the second commandment if it were merely another way of saying the first—there has to be some distinction. During the time of the Old Testament, most kingdoms worshiped carvings and statues made in the image of their gods, such as Zeus or Ra. The first commandment already told us we were not supposed to worship other gods, therefore, it is self explanatory that we should not worship or bow down to their statues. So, why does God give us this second commandment? God was not simply telling His people not to worship the idols of these other nations, but telling us not to create idols and attribute them to Him. The statues and images pagans created were symbolic of their gods, but God was telling us not to create these types of symbols for our worship.
Many Christians either miss or ignore this point. People often hang images of a man they claim to be Jesus in their homes and churches, Catholics kiss the feet of a statue they say is of the apostle Peter, and then, there are the crucifixes and rosaries. Catholics pray holding the rosary. Movies and folklore imbue these symbols with holy power, asserting that the cross will protect from demons and Satan. However, God is not confined to these objects; He lives within us and we don't need them to invoke His power. On top of that, they're misrepresentations of Him. No one today knows what God or Jesus looks like. God appeared to many as an angel, and to Moses as fire. Moses sees God from behind, but there is no image of God included in the Bible because God told Moses not to create them. Think about Tolkien's sketches of Middle Earth included with The Lord of the Rings, or manga, or comics, where authors want you to visualize what they are conveying—God could have easily had someone make sketches of Him, of the Messiah, of angels, of the throne room… Jesus walked on Earth, but no portraits were created of Him—at least if they were, they were destroyed. What is the difference in praying before a statue of Ra and praying in a church with a painting of this random man hanging above the pulpit? Not only are you praying before an image (violation of the 2nd commandment), you are praying before an image that is not the image of God...
4 Thou shalt not make unto thee any graven image, or any likeness of any thing that is in heaven above, or that is in the earth beneath, or that is in the water under the earth. 5 Thou shalt not bow down thyself to them, nor serve them: for I the Lord thy God am a jealous God, visiting the iniquity of the fathers upon the children unto the third and fourth generation of them that hate me; 6 And shewing mercy unto thousands of them that love me, and keep my commandments.
8 Thou shalt not make thee any graven image, or any likeness of any thing that is in heaven above, or that is in the earth beneath, or that is in the waters beneath the earth: 9 Thou shalt not bow down thyself unto them, nor serve them: for I the Lord thy God am a jealous God, visiting the iniquity of the fathers upon the children unto the third and fourth generation of them that hate me, 10 And shewing mercy unto thousands of them that love me and keep my commandments.
This commandment is directly quoted in at least 21 places throughout the Old and New Testaments of the Bible:
2. Exodus 32:8
3. Exodus 34:17
10. Joshua 23:7
12. Psalms 97:7
13. Psalms 115:4-7
14. Isaiah 44:12-20
My understanding of this commandment's importance is directly linked to the ease in which believers can be deceived into following pagan customs such as idol worship under the veil of worshiping God (this is a major problem in the current church, it will be discussed in more detail on the site in the near future). For instance, you can call a full grown tiger a kitten, but that doesn't mean if you try to pet it, it won't bite your hand off. The same is true here, just because you call it an image of Jesus, doesn't make it an image of Jesus and praying before it is still praying before an idol. The second commandment is warning us of this fallacy and reminding us not to try to imitate pagan worship.
The Golden Calf
Perhaps the most notorious example of idolatry in the Bible. God's people created a calf (an animal on earth) and worshipped it as though it was God. They imbued all of the work God did for them into this inanimate object that was worthless. God was so enraged that he threatened to destroy the entire nation right then and there!